Gas fired engines as, e.g., natural gas fired engines, may use gas admission valves to admit the natural gas into the intake channel in spark ignited internal combustion engines. These days in particular solenoid operated gas admission valves (SOGAVs) are used. A SOGAV may be an electrically actuated, high response gas admission valve for in-manifold or port fuel admission. The SOGAV may be designed for use on four-cycle, turbocharged, natural gas or dual-fuel engines. Normally, one SOGAV is required for each cylinder of the engine.
In U.S. Pat. No. 5,329,908 A a compressed natural gas injection system for gaseous fuel engines includes an electronic control unit controlling injection timing to inject compressed gas into cylinders as each piston nears its top dead center position.
U.S. Pat. No. 5,623,907 discloses a liquid propane fuel storage and delivery system for motor vehicle internal combustion engines. This known system includes fuel delivery conduits for communicating propane fuel between a storage tank and engine fuel injectors, and an electric fuel pump.
A vent system for gaseous fuel vehicles is disclosed in U.S. Pat. No. 6,446,616 A. Here, a ventilation system for gas fueled vehicles has a pressure regulator and a relief valve coupled to a fuel line and a vent line, such that gas fuel is coupled to vent line upon an operation of the regulator or the valve.
DE 10 2004 060 905 A1 discloses an internal combustion engine, e.g. a gas line engine and a control method for a vehicle. The control method involves reducing high pressure of fuel at gaseous state up to lowest pressure by a pressure reducer, and controlling lowest pressure by a signal from a control device.
U.S. Pat. No. 7,140,354 B1 discloses a compressed gaseous fuel system for an internal combustion engine. When the pressure in the fuel rail is higher than desired, fuel is withdrawn from the fuel rail, recompressed, and injected into the fuel system for the control regulator. The fuel is withdrawn from the fuel rail by means of a pump. The use of a pump may be likely to result in an inappropriately long response time.
U.S. Pat. No. 7,406,950 B2 refers to a fuel supply apparatus pressure feeding a liquid fuel which tends to be evaporated in comparison with a gasoline in a liquid state to an injector from a fuel tank so as to supply to an engine. Here, a return-less type engine fuel supply apparatus comprises an electronic control unit drive controlling a fuel pipe and injectors and pressurizing a liquefied gas fuel stored in a fuel tank by a fuel pump so as to feed it to the injector through the fuel supply pipe line and supply it to the engine. An electronic control unit feedback controls the operation of the fuel pump on the basis of the detected fuel pressure in such a manner that the fuel injection pressure maintains a predetermined target pressure.
A system for detecting failure of a fuel pressure sensor in an internal combustion engine is disclosed in U.S. Pat. No. 5,983,714 A. In this system, an index indicative of a ratio of the fuel pressure fluctuation relative to the manifold of the absolute fluctuation is compared to reference values which define a range. Sensor failure is discriminated when the index is found to have remained outside of the range for the predetermined maximum time. This system enables rapid and accurate detection of fuel pressure sensor abnormality or failure.
U.S. Pat. No. 5,868,121 refers to a fuel pressure release system for a dual fuel engine including at least one gas use fuel admission valve positioned between a gaseous fuel inlet region and an air intake region. The system includes a first pressure sensor positioned in the gaseous fuel inlet region and a second pressure sensor positioned in the air intake region. An electronic controller is connected to the first pressure sensor and the second pressure sensor. A gaseous fuel vent path extends between the gas use fuel inlet region and a portion of an air intake path of the engine. A vent valve is positioned along the gaseous fuel vent path and is connected to the electronic control of a control thereby. When the differential pressure across the gaseous fuel admission valve exceeds a predetermined level the fuel vent valve is opened to relieve the pressure. This known system is configured to operate in a dual fuel mode. Furthermore, if no dual fuel mode is desired, the vent valve is closed. In dual fuel mode the check of the differential pressure might not provide a solution for a problem as mentioned below.
A problem which may arise in gas fired engines supplied with gas fuel via a gas fuel admission system comprising a gas fuel admission device arranged in relation to a combustion chamber of the engine is that, as a result of an instantaneous load change, where the engine runs at relatively high load and then suddenly under a low load, the engine may over-speed and, consequently, the engine may completely shut down due to an inability to resume fuel injection.
The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of prior gas fired engines using gas admission devices, e.g. SOGAVs. In particular, the present disclosure may be directed to avoid engine shutdowns of a gas fired engine as a consequence of possible load rejection events.